Effect of γ-radiation on structural, morphological, magnetic and dielectric properties of Zn–Cr substituted nickel ferrite nanoparticles

In the present work nano-sized zinc and chromium substituted simultaneously in nickel ferrites Ni 1−x Zn x Fe 2−x Cr x O 4, (Ni–Zn–Cr) nanoparticles with x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 were successfully synthesized through a sol–gel auto-combustion technique using citric acid as a fuel. All the prepared samples have been irradiated by γ-rays of 60 Co source with 7 Mrad at a dose rate of 0.1 Mrad/h to investigate the irradiation effect on the structural, morphological, magnetic and dielectric properties of all the prepared samples. Ni–Zn–Cr nanoparticles were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) to study their structural and morphological changes. The magnetic properties were studied by vibrating sample magnetometer (VSM) at room temperature before and after irradiation. XRD patterns confirm the formation of pure mono-phase of a cubic spinel structure for all the prepared samples. The two prominent absorption bands in FT-IR spectra also confirm the formation of the spinel structure. The FE-SEM image of un-irradiated samples show agglomerated and almost spherical shape particles morphology; while γ-irradiated samples show some scratched morphology. Dielectric constant and dielectric loss tangent decreases with an increasing zinc and chromium concentration of the unirradiated and after γ-irradiated. Overall; the structural, morphological, magnetic and dielectric properties of the present samples were significantly altered after γ-irradiation. Therefore, low dielectric constant and dielectric loss tangent is attractive due to its potential in device applications.